If you want low commish, with less risk, just use a firm like Transact, etc, that caters to high vol traders. If you are not doing volume, don't worry about it, go with security.
I speak from experience. I used a broker that went belly up, and I received only 60% back, two years later! This is futures trading of course, different beast for equities.
I've heard nothing but good things about Vtrader if you want to go work in the SF office and trade in a trading room. Some people make WAY more money this way. No reason to use em if not in their office, IMO.